Tips on ski sunglasses

Many safety glasses are UV 400, and still less than ten pounds
Though bolle don't spec UV400.

Trencher

I phoned my optician, and he said both my reactolite (actually I think they're called transitions) and my sunglasses are both uv 400. But he also said my vari-focal transitions only block out 80% of the visible light at maximum, and the sunglasses only block out 85% of visible light.

Plus, my sunglasses are wrap around, but my transitions are like ordinary glasses.

Ally

The return of the phantom star rater.
How silly.

Tony_H wrote:The return of the phantom star rater.
How silly.

Tony,
I don't get it. Why does one star appear sometimes? And in fact I think I've seen 5 stars appear once. I don't normally see any stars at all.

AllyG wrote:

ise wrote:. To avoid ultraviolet keratitis you need glasses that block all UV light and about 90% of visible light.

Thanks for that Ise, :D and nice to see you back. I had no idea that sunglasses for ski-ing blocked out so much of the visible light. It's amazing we can all see where we're going when we're wearing them!

I generally wear my ordinary reactolite prescription glasses, but I also have prescription dark glasses for ski-ing. I have no idea if they block out enough light to prevent me getting eye damage. Maybe I should check with my optician. I just assumed they'd be okay because I told him I was going to use them for ski-ing.

Ally

As I understand it then it's a little confusing, when you think of blocking visible light you immediately think of something like turning the lights down and that's not really what we're after. What we're after is something more like clipping out some higher frequencies. It's actually this reduction in light in the normally visible spectrum, i.e. frequencies lower than 400nm, that's important for preventing snowblindness. The right tint on any glasses, regardless of their type, together with UV protection is all you need. An expert can slice and dice those EN172 and EN170 scales and work out if any given pair of glasses is any good, the specific three pairs mentioned above don't appear to filter out enough light to me but you'd need to ask an optician to be 100% sure, I think EN172 and EN170 both define some altitude measures although it's a specialized area and a lot of the standards are over my head. Asking an optician or using models developed for this specific environment is better.

That's not to say some sunglasses are a bit overpriced, I don't use Oakleys personally as they look a bit dear, I do use Bollé, Cebe and Alpina with Bollé probably being my optic of choice at extreme altitude. They're not too expensive and a concern over breaking or loosing them is a bit of a red herring, I don't carry anything I don't actually need at extreme altitude so I can't afford to lose my glasses whether they cost me 10 quid or a 100 quid.

I would imagine reactolite glasses are fine, personally I'd not choose to wear them personally, I'm still dubious that they really react quick enough despite recent advances and I don't believe they're really effective at very high or extreme altitude in purely visual terms where I think the weighting of light to the higher frequencies would make them too dark to be useful at times. But that's a personal choice about vision based on my opinion not something based on any information about them not being safe.

AllyG wrote:

Tony_H wrote:The return of the phantom star rater.
How silly.

Tony,
I don't get it. Why does one star appear sometimes? And in fact I think I've seen 5 stars appear once. I don't normally see any stars at all.

Someone decided to rate a post. You can rate anyones post if you want, but I dont see the point in doing it TBH. I used to sometimes, but its a bit daft.
However, some people go around deliberately giving some members low ratings and over time this brings their star rating down which gives the impression they are not liked so much, and some peolpe deliberately go bigging up their friends or heroes. It has been suggested that some members have an alter ego or sock puppet (sound familiar?) who log on and give their other membership name a high rating.

You may be able to work out who likes who on here, and who doesn't by the stars being awarded, although I dont think it is possible to find out who has rated who. Its all quite complicated and IMO quite pathetic.

I only star rate a post if it is special - especially good or especially bad.

Caraon-a for example doesnt like negative or provocative posts, and is likely to 1 star them.

I'll leave the rest for you to work out.

Tony_H wrote:

AllyG wrote:

Tony_H wrote:The return of the phantom star rater.
How silly.

Tony,
I don't get it. Why does one star appear sometimes? And in fact I think I've seen 5 stars appear once. I don't normally see any stars at all.

Someone decided to rate a post. You can rate anyones post if you want, but I dont see the point in doing it TBH. I used to sometimes, but its a bit daft.
However, some people go around deliberately giving some members low ratings and over time this brings their star rating down which gives the impression they are not liked so much, and some peolpe deliberately go bigging up their friends or heroes. It has been suggested that some members have an alter ego or sock puppet (sound familiar?) who log on and give their other membership name a high rating.

You may be able to work out who likes who on here, and who doesn't by the stars being awarded, although I dont think it is possible to find out who has rated who. Its all quite complicated and IMO quite pathetic.

I only star rate a post if it is special - especially good or especially bad.

Caraon-a for example doesnt like negative or provocative posts, and is likely to 1 star them.

I'll leave the rest for you to work out.

I was given 5 stars recently a couple of times and couldn't for the life of me work out why?

AllyG wrote:I phoned my optician, and he said both my reactolite (actually I think they're called transitions) and my sunglasses are both uv 400. But he also said my vari-focal transitions only block out 80% of the visible light at maximum, and the sunglasses only block out 85% of visible light.

Plus, my sunglasses are wrap around, but my transitions are like ordinary glasses.

Ally

More importantly though, what was his expert opinion? Did he reckon that they were good enough?

You've mentioned another good point as well, the shape of glasses, it doesn't matter how much light the lens blocks if it's all just coming round the side anyway.